1. Field of the Invention
The invention relates to a chair, more specifically, to a chair with a synchronous coordinating system for the chair back, wherein the synchronous coordinating system can be cooperated with the rotation of the human body.
2. Discussion of the Related Art
Presently, there are two connection modes for the chair cushion and the chair back. One is the chair whose chair cushion and chair back are connected fixedly and can not rotated each other, such as most of the chairs for the dining table, which is only adapted to use for a short time. The other is the chair with the adjustable-angle chair back, which is adapted to the office chair seated for a long time. Since such chair can not only be seated but also provides a supporting force to the upper part and the waist of the human body by means of the chair back, the correct posture of the waist of the human body can be kept and the tiredness of the waist can be reduced. In the meantime, the angle between the chair back and the chair cushion can be adjusted according to different requirements (the angles of the chair back and the chair cushion can be adjusted as a whole), so that the chair is facilitative to be used.
However, such chair has some structures designed improper, thus once the angle of the chair back is rotated in use, the position for supporting the waist of the human body will be changed. Therefore the chair can not support the upper part and the waist of the human body sufficiently. Additionally, friction will be generated between the chair back and the waist, which makes the backside of the human body uncomfortable (for example, the clothing of the person can be drawn away by the friction).
For this, the invention provides a chair with a synchronous coordinating system for the chair back so as to solve the problems of the present chairs effectively.